A list of the tests P&S monitoring augments and the related features, functions, and benefits are included in Appendix 3. This is another consequence of the fact that the P and S control and coordinate the organs and systems of the body. Many ancillary tests test the end organ. Most organs or organ systems are controlled by muscles: cardiac or smooth. All muscles are controlled by nerves, and the nerves that control cardiac and smooth muscles are the P and S nerves. P&S monitoring completes nervous system studies that tend to not include the ANS. P&S monitoring serves as a “mini-Holter,” “mini-tilt,” and “mini-stress” study. P&S monitoring also provides information that represents the extra day(s) patients used to stay in hospital to document stability prior to discharge.

In the sense of a “mini-Holter,” the DB challenge simulates a patient’s response to disease and therapy after meals, after exercise, and before bedtime. The Valsalva challenge simulates a patient’s response to exercise and stress. The resting and standing challenges fill out the rest of the day. The Holter data not simulated are the reason that P&S monitoring is augmentative. The “mini-tilt” comparison is based on P and S changes from resting to standing as discussed and documented elsewhere [8]. Again, the data not simulated are the reason P&S testing is augmentative. The “mini-stress” test is provided by the Valsalva challenge. Valsalva models patients’ responses, given their history, to all significant stressors, including exercise and physical, psychological, physiologic, and emotional stressors.

P&S monitoring documents patient responses to disease, therapy, lifestyle, genetic predisposition, history, and rehabilitation, as well as changes in these factors. Given that P&S monitoring enables early detection of changes in physiologic state, P&S monitoring promotes wellness proactive medicine and primary care, as well as secondary care and emergency medicine. P&S monitoring supports the US Congress’ mandates (2003 Medicare Modernization Act and 2010 Patient Protection and Affordable Care Act) for evidence-based and value-based medicine and comparative benefit analysis.

The many tests that P&S monitoring is augmentative include cardiac muscle tests (including EKG, stress, tilt, Holter, event, sitting standing BP, cardiac output, and imaging tests), vascular muscle tests (including Doppler and ultrasound tests and ankle-brachial index), pulmonary muscle tests (including the pulmonary function tests and spirometry), GI muscle tests (upper and lower), and other smooth muscle function (e.g., endocrine and sweat glands and urogenital function) (see Appendix 3). As you know, muscle dysfunction may indeed be due to disease or damage to the muscle, but muscle dysfunction may also be due to P or S nerve dysfunction. P&S monitoring enables physicians to differentiate muscle from nerve function. Each time one of these other ancillary tests is ordered, P&S monitoring may also be ordered.

P&S monitoring is also augmentative to several neurological tests (e.g., nerve conduction velocity (NCV), vestibular testing, and pain testing; Q-SART (Q-Sweat) studies; thermal studies; and EEG and brain imaging; see Appendix 3). NCV testing measures sensory-motor fibers (A and B fibers) and misses the “C” fibers, including P and S fibers. P&S monitoring captures what is missed. Vestibular testing documents only one of the four general causes for vertigo, dizziness, or lightheadedness. The other three include arrhythmia, syncope, and orthostasis. The PSNS and the SNS are involved in all of the other three. For pain studies, there are few, if any, objective tests for pain. P&S monitoring objectively quantifies sympathetic responses to pain. P&S monitoring (1) objectively quantifies pain level; (2) differentiates non-physiologic (e.g., psychosomatic) pain, from physiologic (e.g., somatosensory) pain, from chronic regional pain syndromes (CRPS formerly reflex sympathetic dystrophy); (3) aids in titration of the often addictive pain therapy; and (4) documents rehabilitation (see Chap. 24). Q-Sweat (Q-SART of pseudomotor) studies test specifically for peripheral autonomic neuropathy. P&S monitoring is sensitive to the effects of peripheral as well as central autonomic neuropathy. Thermal studies consider specific sweating abnormalities, and the ANS, of course, controls sweat glands. For EEG and brain imaging, P&S monitoring differentiates the autonomic brainstem from cortical activity.

Data collected for the Autonomic (P and S) Assessment include EKG samples at 250 Hz or more, continuous respiratory activity samples at 60 Hz or more, and six noninvasive BPs (one per phase of the clinical exam). These data are collected using a standard FDA-approved bedside monitor and processed through CWT analyzers in 4 s intervals. From these signals the heartbeat interval (HBI) or instantaneous HR (aka, the cardiogram) and the continuous LFa, RFa, and LFa/RFa ratio waveforms are computed at 0.25 Hz. Averages of these signals are computed over the time frames of the phases of the clinical exam (see Table 6.1, duration column), resulting in mean HR (mHR), fundamental respiratory frequency (the FRF: approximately the mean breathing frequency), LFa (the sympathetic measure), RFa (the parasympathetic measure), and LFa/RFa ratio (the SB measure). Also computed for each phase of the clinical exam are the frequency-domain and time-domain HRV-alone parameters (VLF, LF, HF, LF/HF, TSP, LFnu, HFnu, and sdNN, rmsSD, pNN50) as defined in the “HRV – Standards of Measurement” Special Report [9, 10]. The HRV-alone parameters are processed through a short-term FFT analyzer at 32 s intervals as per the standard articles. The statistical HRV parameters (range HR, max/min HR) are computed for each phase of the clinical exam, and the time-domain ratios (the E/I ratio, the Valsalva ratio, and the 30:15 ratio) are computed from the appropriate phase of the Autonomic Assessment study, according to the standard articles.

P&S monitoring includes fully automated software able to guide the technician, as a “coach,” in administering the test to the patient and ensuring the patient performs the test properly. Again, with the advent of wavelet spectral analysis techniques, only cardiac pacemaker patients with pacers actively pacing throughout the test are contraindicated for P&S monitoring. Pacers that are actively pacing for only one or two phases of the test are acceptable, since pacing indicates a clinical end point that correlates with the autonomic branch being stimulated. The same holds for arrhythmia. While arrhythmia is contraindicated for HRV-alone monitoring, P&S monitoring is not. In some cases, isolated arrhythmic beats may be “corrected” by the software according to FDA-approved methods, enabling P&S monitoring to proceed in the usual manner (see Chap. 18). In some cases, the arrhythmia occurs during only certain phases of the P&S study. In these cases the arrhythmia may be considered as a “symptom” or clinical end point that correlates with the autonomic branch being stimulated. Arrhythmia still obscures the absolute values of the P&S results (due to the HRV component). For example, if there is arrhythmia in only the DB challenge, a strong parasympathetic activity is implicated in triggering the arrhythmia, suggesting a PE. Since this is an autonomic indication and is treatable, P&S monitoring is proven clinically relevant. In the remainder of the cases, the arrhythmia is throughout the test (or much of it), which leaves only the (resting) SB [11] as the readable parameter. Since SB involves both ANS branches, these results still provide P and S information which is treatable. Abnormal SB in the presence of arrhythmia suggests a possible autonomic involvement in the arrhythmia: high SB suggests a resting, excessive sympathetic component to the arrhythmia, and low SB suggests a resting, excessive parasympathetic component. Normal SB suggests no autonomic involvement in the arrhythmia. This has been shown many times in the clinic for ventricular arrhythmia patients as well.